- Flight category definitions:
| Category |
Ceiling |
|
Visibility |
Low Instrument Flight Rules
LIFR* (magenta sky symbol) |
below 500 feet AGL |
and/or |
less than 1 mile |
Instrument Flight Rules
IFR (red sky symbol) |
500 to below 1,000 feet AGL |
and/or |
1 mile to less than 3 miles |
Marginal Visual Flight Rules
MVFR (green sky symbol) |
1,000 to 3,000 feet AGL |
and/or |
3 to 5 miles |
Visual Flight Rules
VFR+ (blue sky symbol) |
greater than 3,000 feet AGL |
and |
greater than 5 miles |
*By definition, IFR is ceiling less than
1,000 feet AGL and/or
visibility less than 3 miles while LIFR is a
sub-category of IFR.
+By definition, VFR is ceiling greater than
or equal to 1,000 feet AGL and visibility greater
than or equal to 3 miles while MVFR is a
sub-category of VFR.
|
- Cloud coverage symbols:
Automated stations report "CLR" when clouds may exist
above 12,000 feet so a square is used to represent this
uncertainty whereas an unfilled circle is used for "SKC"
which a human reports the sky is completely clear overhead.
The abbreviation "OVX" is unofficial but ADDS uses it
here to indicate the sky is obscured which is the case when a
METAR reports vertical visibility and no cloud information.
|
